Recently there has been a trend in replacing conventional incandescent light bulbs with light emitting diodes (LEDs). For example, traffic control signals and automobile brake lights are now manufactured using LEDs. The replacement of conventional incandescent light bulbs with one or more LEDs is desirable because incandescent bulbs are inefficient relative to LEDs, e.g., in terms of energy use and longevity.
Certain lighting applications, however, pose particular problems for replacing incandescent bulbs with LEDs. For example, some highly noticeable lighting applications, such as accent or spot lamps, require white light with a particular correlated color temperature (CCT). Replacing incandescent light bulbs with LEDs in such lighting applications is problematic because of the difficulty in controlling the spectral distribution, i.e. the CCT or white point, of the LEDs. Moreover, when replacing incandescent light bulbs, it is important that the LED light source have a compact form factor, e.g., that is no larger than the incandescent light bulbs, which increases complications. Further, there is a desire for color tunable lamps, which can be adjusted, e.g., for mood, scene and personal preferences. Accordingly, improvements in LED light sources that can produce white light is desired.